In the case of a bottle or other container for a branded liquid product, such as an alcoholic beverage, once the original product has been emptied from the bottle it is known to refill the bottle with a counterfeit beverage and then display the refilled bottle with its original product labels in place but now containing the counterfeit beverage. In locations, such as bars and restaurants, where a branded beverage is dispensed as an individual drink rather than by the bottle it is known that substantial losses are sustained by manufacturers of the branded products by such counterfeiting. A similar problem can arise with other liquids such as oils. Where such counterfeiting occurs, for example, with an engine lubricating oil then use of the counterfeit product under the mistaken impression that it is a genuine one can result in damage to an engine with possible safety hazards.
A number of proposals have been made in the past to make it difficult for a person seeking to counterfeit beverages in this way. UK Patent 694389 (Favre) shows a liquid dispensing closure for the neck of a vessel comprising a stopper arranged to be held against or in the neck of the vessel by a capsule fitting tightly around both the stopper and a part of reduced diameter on the neck, a pair of independent passages of substantially uniform cross section in the material of the stopper, each passage terminating on the bottom of the stopper in independent free communication with the interior of the vessel and near the top of the stopper in independent free access to the outside by way of a common orifice in the side of the capsule, the arrangement being such that when the neck of the vessel is lower than the bottom, one of the passages is in the form of a normal syphon with a priming part reaching from the interior of the vessel to the end of the shorter leg of the syphon while the other passage includes in series from the interior of the vessel an orifice of smaller cross section than the remainder of the passage and an inverted syphon that is, a syphon having the second property hereinbefore described.
U.S. Pat. No. 4,532,687 (Hullihen) describes a non-refillable pour spout for use in the neck of a bottle for permitting liquid to be poured through said spout from within said bottle but resisting replenishment of the liquid of the liquid in said bottle, comprising: a generally cylindrical spout member having a top and bottom and adapted to fit sealingly within the neck of the bottle; a liquid pouring duct extending through said spout body member and including discharge tube means for defining a liquid discharge opening adjacent the top of said spout body member; a first check valve located in said pouring duct in said spout body member, including a first valve seat and a movable first valve closure body held within said spout body upwardly adjacent said first valve seat, said first check valve communicating with said discharge tube means; a second check valve located in said liquid pouring duct in said spout body member, including a second valve seat and a movable second valve closure body held within said spout body upwardly adjacent said second valve seat, said second check valve being located beneath said first check valve and communicating with said first check valve; an air inlet tube attached to said spout body member and having a lower end extending downwardly therebeneath; an air inlet conduit having an open upper end located in said top of said spout body member, said air inlet conduit extending through said spout body member and said air inlet tube, from said top said spout body member to said lower end of said air inlet tube; and a third check valve located in said air inlet conduit, including a valve seat and a movable third valve closure body held within said air inlet conduit and located upwardly adjacent said third valve seat.